Many modern vehicles are fitted with systems (anti-lock braking, adjustable ride height etc.) designed to improve the riding experience of the users. The riding experience could be a measure of, for example, vehicle composure or comfort, and the setup of the systems of a vehicle to optimise the riding experience can be dependent on the type of terrain over which the vehicle travels. Current systems have defined system configurations for a plurality of different terrain types. In a vehicle terrain response system (VTRS), such as Terrain Response®, the user may determine the terrain type over which the vehicle is travelling, or determine the terrain type ahead of the vehicle, and manually input this information into a vehicle control system (VCS) which then adjusts the configuration of the systems appropriately. Alternatively, the vehicle may be fitted with sensors designed to measure certain characteristics of vehicle subsystems (such as wheel acceleration, wheel slip, steering force estimator etc.) that are indicative of the terrain type over which the vehicle is travelling. Based on these measurements, the VTRS may determine the terrain type that most likely fits with these characteristics, and adjust the configuration of the systems appropriately, for example as described in GB patent application GB2492655. However, the determination of a terrain type by examining vehicle parameters using on-board systems is a reactive solution to the terrain over which the vehicle is currently travelling and as such does not allow the vehicle to prepare in advance for the terrain over which it is about to travel without user-input.
It is, however, desirable that a vehicle system could remotely determine the terrain type in the vicinity of the vehicle. This is desirable because the user controlling the vehicle may be unaware of possible hazards (slippery surfaces caused by water, ice, snow, wet grass etc.) in the vicinity and therefore it is necessary that either the vehicle prepares for the hazard automatically or the user controlling the vehicle is alerted. This is desirable also because automated moving devices (robots, unmanned vehicles, automatic aircraft landing systems etc.) are becoming increasingly important and do not have user-input available to prepare for the terrain in the vicinity.
Different types of vehicle-mounted sensors may be used to collect data for a plurality of different parameters indicative of the terrain over which the vehicle is currently travelling. The collected data for a particular terrain type may contain a reasonable amount of noise between readings. For example, the collected data for grass may vary depending on the length of the grass. The collected data may also contain outlying data points: this may be caused by, for example, objects on the terrain surface. It is desirable that, when determining a terrain type, a vehicle system can process collected data containing noise and outlying data points in such a way as to identify certain characteristics that relate to each terrain type. In addition, different parameters may show greater differences in the collected data between different terrain types in different situations. It is therefore also desirable that the vehicle system can deal with a large number of parameters, and select the optimal set of parameters with which to determine the terrain type.
One object of the present invention is to provide a vehicle system that is configured to process sensor output data to identify certain characteristics relating to a particular terrain type and to determine an indication of the terrain type in the vicinity of the vehicle based on these identified characteristics, that addresses the difficulties described above in such a way that the systems in the prior art cannot.